Forgot?
Pregnancy
Gestational Age
Ultrasonography, Prenatal
Prenatal Diagnosis
Amniocentesis
Down's Syndrome
Fetal Diseases
Second Pregnancy Trimester
Sensitivity and Specificity
Prospective Studies
ROC Curve
Maternal Age
First Pregnancy Trimester
Risk Factors
Biological Markers
beta Subunit Human Chorionic Gonadotropin
Chorionic Gonadotropin
Estriol
False Positive Reactions
Newborn Infant
Co-Publications
28
27
25
14
13
10
9
8
6
Flash Player Required